Roman shade

ABSTRACT

An improved expandable and contractible window covering comprising a series of elongated cells is disclosed. Each cell is formed by joining two pleated sheets of material in the area of opposing creases. The rear wall of the cell is of less height than the front wall of the cell, and the material of the cell is chosen to be relatively soft and flexible, so that the front wall of each cell droops downwardly and outwardly away from the rear wall.

This application is a continuation of application Ser. No. 08/085,677filed Jun. 30, 1993, now abandoned, which was a continuation ofapplication Ser. No. 07/825,591 filed Jan. 24, 1992, now abandoned,which was a division of application Ser. No. 08/520,932 filed May 9,1990, now U.S. Pat. No. 5,104,469.

FIELD OF THE INVENTION

This invention relates to an improved window covering. Moreparticularly, this invention relates to an improved window covering ofthe Roman shade type wherein one side of the shade, typically arrangedso that this side is toward the interior of a room, consists of a numberof horizontal parallel curved surfaces, and in which each of thesecurved surfaces forms the front wall of a tubular cell extendinghorizontally across the width of the shade, thus creating a thermalinsulating window covering with an extremely attractive appearance.

BACKGROUND OF THE INVENTION

Several publications show cellular shades, wherein a fabric material isformed to define parallel tubular cells extending horizontally acrossthe width of the shade. Air within each of the cells only circulatesminimally, such that when expanded the shades provide good thermalinsulation.

It is, of course, desirable to make the physical appearance of the shadeas attractive as possible. Similarly, it is desirable to make suchshades as economically as possible, which requires both that a minimalamount of material be used to form each cell and that the manufacturingprocess be as expeditious as possible.

Various exemplary prior art disclosures include the following:

Terrel U.S. Pat. No. 2,201,356 discloses a window shade made by joiningtwo folded sheets having interior and exterior folds. FIGS. 4 and 5 showan asymmetrical embodiment where the interior folds of one sheet arejoined to the exterior folds of the other sheet.

Yasui U.S. Pat. No. 3,892,898 relates to a honeycomb panel core havinginterlocking expandable and contractible W-shaped and V-shapedcomponents disposed between partition plates.

Brown U.S. Pat. No. 4,347,887 shows a "thermal shutter". A wide band ofmaterial is folded transversely to form a double row column of adjacentcells, which may have rounded visible contours. The cells are adhesivelybonded to one another. The Brown structure is symmetrical, so that bothsides of the shade thus formed have essentially the same appearance.

Anderson U.S. Pat. Nos. 4,631,217, 4,676,855 and 4,677,013 show in FIG.3 a shade of asymmetrical construction. A rear wall section of each cellis essentially straight or linear when the shade is in its expandedposition. The width of these rear wall sections thus defines the spacingof the adjacent cells, while the front of each cell, containing morematerial, maintains a non-linear shape.

Anderson U.S. Pat. No. 4,685,986 shows in FIGS. 1 and 3 shades of nearlysymmetrical construction and symmetrical construction, respectively. Thecellular shade is formed by joining two pleated lengths of materialalong opposing pleats. FIG. 6 shows an asymmetrical embodiment of theinvention, in which the rear wall is essentially straight when the shadeis in its expanded position.

Schneider U.S. Pat. No. 4,846,243 shows a foldable window coveringformed of a wide relatively soft material folded transversely, as in theBrown patent, to yield a collapsible shade. The front surface of theshade consists of a material doubled back on itself. The successivecells are spaced in the expanded position of the shade by a relativelyvertical rear wall section of each cell.

Neff U.S. Pat. No. 4,861,404, owned by the assignee of the presentapplication, shows a method of making a honeycomb product from twosheets of pleated material. Alternating pleats are formed of large andsmall dimensions, and end parts of the large pleats are then bondedtogether to form leg portions. These leg portions are then joined toopposing pleats of another sheet.

Sevcik et al. U.S. Pat. No. 5,097,884 shows a Roman shade type windowcovering, made by joining successive folded strips of material using amanufacturing process as-exemplified by Colson U.S. Pat. No. 4,450,027.The product in that application has substantially the same appearance asthat of the present invention, but its structure and the process ofmanufacture are different.

SUMMARY OF THE INVENTION

It is an object of,the invention to provide an improved Roman shadeconsisting of a series of parallelly arranged generally tubular cells,each having a front wall which consists of a loop formed of a softmaterial which is essentially uncreased in the finished product, suchthat the loop droops somewhat, providing an aesthetically pleasingappearance, while the rear wall of each cell is essentially linear or ofother configuration so that when the shade is in the expanded state, theheight of the rear wall determines the spacing of adjacent cells andholds the loop of the front wall from being pulled out.

It is a further object of the invention to provide a shade which can bemanufactured using essentially methods and apparatus as shown, forexample, in the Anderson U.S. Pat. No. 4,685,986.

These and other objects of the invention which will appear to thoseskilled in the art are met by the present invention, which comprises animproved Roman shade consisting of a series of parallel cells formed byjoining two lengths of material at opposing, inwardly-directed pleats.Each cell includes a rear wall portion, which determines the spacing ofthe cells when the shade is in its expanded state, a top portion, afront wall portion defining a generally drooping curved surfaceextending in a curve from the top portion of the cell downwardly andaway from the rear wall portion, and a bottom portion extending from thefront portion to the rear wall and defining, at least in part, the topof the next underlying cell. The cell front surface provides anextremely attractive appearance. The shade may be manufactured generallyusing the techniques and apparatus shown in the Anderson U.S. Pat. No.4,685,986.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a first embodiment of the shade of the invention in itsnearly collapsed state;

FIG. 2 shows the shade of FIG. 1 in its expanded state;

FIG. 3 shows a cross-sectional view of the embodiment of FIG. 1 in theexpanded state showing the individual cell structure of the shade;

FIG. 4 shows a cross-sectional view of a second embodiment of the shadeof the invention in the expanded state showing the individual cellstructure of the shade;

FIG. 5 shows a cross-sectional view of the embodiment of FIG. 1 in thenearly collapsed state;

FIG. 6 is a schematic view showing the manufacturing process employed inproducing the cellular structure of FIG. 3;

FIG. 7 is a schematic view showing the manufacturing process employed inproducing the cellular structure of FIG. 4;

FIG. 8 is a schematic view showing a first alternative pleating andjoining process according to the present invention; and

FIG. 9 is a schematic view showing a second alternative pleating andjoining process according to the present invention.

FIG. 10 is a cross-sectional view of the embodiment of the inventionmade in accordance with the process illustrated in FIG. 9.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

As indicated above, FIGS. 1 and 2 show the shade of the invention in itscollapsed and expanded states. As can be seen, the shade comprises aseries 1 of parallelly arranged cells 2 extending horizontally. Theseries of cells 2 is fitted with a bottom rail 3 and a head rail 4(omitted from FIG. 2 for clarity). The series is adapted to be fittedinto a window opening, for example, with the longitudinal cell axistransverse to the direction of expansion and contraction of theassembly. The motion of the shade between the collapsed state of FIG. 1and the expanded state of FIG. 2 is controlled by control cords 5extending from the bottom rail 3 upwardly across the cells 2, and intothe head rail 4. The cords are directed by generally conventionalcontrol pulleys, guides and the like, and are engaged by a conventionallocking dog engaging mechanism (not shown).

As indicated in FIGS. 3-7, the cells 2 are formed by two sheets offlexible fabric material, each having a set of transverse creasesdefining pleats, and the sheets are joined to one another in the area ofconfronting, inwardly-directed creases 20, 22 (i.e., the creases whichpoint toward the center of the shade when complete). A first sheetcommonly defines back faces of the cells, and a second sheet commonlydefines front faces of the cells, the faces being those portions whichare visible when the shade is in use. Preferably, the sheet which makesup the back of the shade has a second set of outwardly-directed creases21 to aid in the manufacture and operation of the shade. Each cell 2 hasa cross-sectional shape including a drooping front wall 11 extendingdownwardly from the top portion of each cell and projecting outwardlyand away from its back face, so that each cell is wider toward itsbottom. Preferably, the material of the front wall 11 of each of thecells is of sufficiently greater height compared to the rear wall 8 thatthe front bottom portion of each cell droops downwardly at least as faras the juncture between the cell-and the directly adjacent lower cellwhen the shade is in the expanded state. Accordingly, when the shade isin its collapsed state as shown in FIG. 1, the drooping loop formed byeach cell extends well below the juncture with the adjacent lower cell.

As can be seen from FIGS. 3 and 4, the cells 2 making up the series 1are formed by fixedly joining two pleated sheets of material in the areaof their confronting, inwardly-directed creases. In this way, thepleated sheets are formed into a series of tubular cells with open ends.As typically used, these shades are disposed between opposed surfaces ofthe casing of a window. The width of the shade is preferably chosen sothat the ends of the cells approach the casing closely, such that littleair flow takes place through the cells. In this way, the air mass ineach cell is essentially static, whereby the cells of air form veryeffective thermal insulation.

According to the embodiment of the invention shown in FIG. 3, thepleated sheets of material are joined by beads 6 of adhesive atconfronting creases 20, 22 which partially overlap each other. One ofthese sheets 18 defines a rear wall portion 8 extending downwardly froma top rear portion 7, and a bottom rear portion 9 extending forwardlyfrom the rear wall portion. A second sheet of pleated material 19defines a front wall portion 11 extending downwardly from a top frontportion 12, and a bottom front portion 10 extending rearwardly from thefront wall. The top front portion 12 of one cell is bonded by the bead 6of adhesive to the bottom rear portion 9 of the adjacent upper cell.Alternatively, the top rear portion 7 of one cell could be bonded to thebottom front portion 10 of the adjacent upper cell. The formed cells incross-section effectively define continuous closed loops of material.

According to the preferred embodiment of the invention, it is desirablethat the cell be asymmetrical such that the rear wall portion 8 is ofsubstantially less height (as measured in the vertical direction of thefinal window covering, transverse to the longitudinal axis of the cell)than the front wall portion 11. Thus, the rear wall portion woulddetermine the amount of cell expansion which is possible. In this way,each cell can be arranged to be of predetermined height from the top tothe bottom of the shade, for effecting the desired appearance.

The extent of cell expansion of the assembly is thus controlled by theheight of the rear wall portion 8 of each cell; this, together with theamount of material in the front wall portion, determines the curvatureof the generally curved surface of the front wall portion 11 of thecell.

It is also preferred that the entire sheet be formed of a relativelysoft and flexible fabric material so that in the expanded position shownin FIG. 3, the front wall portion 11 droops downwardly and outwardlyaway from the rear wall 8, forming a smoothly sounded curve. Typically,the lowest part of the front wall portion is level or beneath thejuncture of the cell with the directly adjacent lower cell. Thisprovides an extremely attractive appearance. It is further preferredthat the front wall portion not be creased perceptibly when the shade isin use, principally for aesthetic reasons.

It is not necessary that both sheets be pleated. One sheet may beprovided with a first set of pleats, which are joined at intervals alongthe length of a second, unpleated material. Among the alternativeembodiments of the invention, a minimum of one set of pleats on onesheet is therefore required.

A temporary crease to assist in manufacture of the shade of theinvention can be provided in a number of ways. For example, in order toform a permanent crease in a polyester film material, it is necessary toheat the material to a given temperature while folding it and to pressit against a hard surface to form a sharply set crease. However, atemporary crease can be formed during the manufacturing process bypressure with a limited amount of heating. If the shade is then hung andallowed to expand, and the crease is heated above a transitiontemperature, the polyester material will tend to return to its originalshape, so that the temporary crease will effectively disappear.

Similarly, a cotton fabric with a water soluble sizing such as starchcan be used to form the shade of the invention. Such a sized cottonfabric can be creased as if it were paper. However, the starch can bedissolved if the shade is subsequently hung out and wetted, removing thecreases. Similar techniques may be useful with polyester and syntheticmaterials.

It is possible to form the shade of the invention from materials whichdo not crease, such as elastomeric materials.

The basic method of forming the series of cells of the embodiment ofFIG. 3 includes an initial step of folding the sheets of material into apleated form as shown in FIG. 6. The basic method is fully disclosed,most particularly at column 4, line 15 through column 6, line 50, in theAnderson U.S. Pat. No. 4,685,986, which patent is incorporated herein byreference.

The basic method of forming the series of cells of the embodiment ofFIG. 4 as shown in FIG. 7 is similar to that of FIG. 6 but employsseparate strip material 28 between opposing, inwardly-directed creases20, 22 to join the two sheets. This method is also disclosed in AndersonU.S. Pat. No. 4,685,986.

As indicated above, it is an object of the preferred embodiment of theinvention to provide a shade having cells each with the appearance of asmooth and uncreased curved front wall portion 11, and in whichpermanent creases are avoided during assembly. In the Anderson processshown in U.S. Pat. No. 4,685,986, an expandable-collapsible honeycombstructure is provided from two pleated lengths of material; one of thesematerials will form one side of the honeycomb structure, while the otherwill form the other side. Thus, they can be made of the same ordifferent material. Also, the creases in the material can be formed aspart of the honeycomb forming process or can be preformed. In any event,the pleated materials are joined together along their creased areas.Permanently creasing the front wall portions in the same manner as inthe Anderson process is avoided, to provide smooth front wall portionsfor the sake of appearance.

FIGS. 6 and 7 of the present application partially show the apparatus ofthe '986 patent, as used in accordance with the teachings of the presentinvention. In both figures, the two sheets of material are attached inthe area of confronting, inwardly-directed creases.

As shown in FIG. 6, the honeycomb structure 17 is formed by continuouslyfeeding a continuous length of each of the materials 18 and 19longitudinally of their length and in directions extending toward eachother. The first material 18 has a first set of transverse creases 20.The first material also has a second set of transverse creases 21 spacedalong the length of the material in alternating fashion with andopposite to the first set of creases 20. The second piece of material 19has only a first set of transverse creases 22. The first sets of creaseson both materials permit the materials to collapse in the accordionfashion shown in FIG. 6 where the creases define the points at which thematerial folds for the shade to collapse.

As the first and second materials are fed in opposite directions, theyare fed along a first path in partially collapsed condition. As theynear each other, they are progressively brought into and fed along acommon second path. With the embodiment of the honeycomb structure shownin FIG. 6, the successive confronting and inwardly-directed creases 20and 22 of the two pieces of material are brought into partiallyoverlapping relationship as they are turned from their first path intothe common second path and they are then directly attached together inthis overlapping relationship. For this purpose, adhesive may be appliedto one or both of the materials adjacent the creases 20 and 22. FIG. 6shows schematically an adhesive applicator at 24 for applying a bead ofadhesive 25 to one side of each of the creases 20. This adhesive mayextend the full length of the crease or may be applied intermittently.

As the successive confronting creases 20, 22 are brought intooverlapping relationship, they are supported by suitable backupstructure 26, while a pressure member 27 moves down onto the, overlappedcreases to press them into adhering relationship. The backup structure26 can be intermittently moved into and out of supporting relationshipand can also be used to move the combined cell structure downwardlyalong the second common path after each set of creases is securedtogether. After the materials are joined together, they are collected intheir common path. Throughout the process, formation of permanentcreases in the front faces of the cells is avoided. Details of thisprocess are found in Anderson U.S. Pat. No. 4,685,986.

The confronting, inwardly-directed creases 20, 22 aid in the folding ofthe two materials in accordian pleated fashion as the cells are moved toand from collapsed and expanded condition. The first material 18 has anadditional set of outwardly-directed creases 21, in alternating relationwith creases 20, which will also aid in the folding of the two materialsand will give the shade a pleated appearance on one side. The othermaterial does not have outwardly-directed creases, but rather is allowedto fold up in accordian-like fashion while providing a smoothly-curveddrooping surface when the window covering is completed. Temporarycreases or smooth folds may be formed at 23 to aid in the manufacturingprocess. The distance between creases 22 is greater than the distancebetween creases 20, in order that material 18 provides a rear wall ofthe shade which determines the maximum possible expansion of the shade.Material 19 therefore will provide the drooping appearance desired forthe shade even in the fully expanded state.

Further, as seen from FIG. 6, the connecting of the adjacent cellstogether is effected while the two materials 18 and 19 are maintained inpartially expanded condition. Thus, any bleeding of adhesive through thematerials during the adhesive application or pressing operation will notcause any severe manufacturing problems. With the present invention, itis only desirable that the cells remain in their partially expandedcondition until the adhesive is set, but the thickness of material inthe area of attachment should prevent manufacturing difficulty.

With reference to FIG. 7 showing schematically the method of manufactureused in producing the honeycomb structures of FIG. 4, the two pieces ofpleated material are fed along a first path, and as they are turned intoa second common path, the creases 20, 22 are brought into laterallyspaced relationship with each other. As each pair of associated creasesattains this relationship, a piece of strip material 28 is brought intooverlying relationship with the creased areas and joined thereto. Forthis purpose, suitable support means 26' and a cooperating pressuremember 27' are used, similar in construction and operation tocorresponding means shown in FIG. 6. Details of this method may be foundin Anderson U.S. Pat. No. 4,685,986.

An alternative manufacturing process, shown in FIG. 8, both pleats andjoins the materials to form a shade similar to that shown in FIG. 7. Theadditional step of pleating materials 18 and 19 is carried out,respectively, by first reciprocating forming knife 31 and secondreciprocating forming knife 32. Second forming knife 32 has a curvedsurface 33 on one side to avoid creasing material 19 on its surface overwhat will be the front faces of the cells. Support structures 34 providethe surface against which the forming knives press the materials duringpleat formation. Surface 35 further assists the first forming knife 31by providing a surface against which outside pleats 20 can be formed onmaterial 18. The remainder of the process shown in FIG. 8 issubstantially the same as shown in FIG. 7.

Another alternative manufacturing process is shown in FIG. 9, which maybe used to form the shade of the invention where only one set of pleatsis formed on one sheet of material as shown in FIG. 10. As FIG. 9 shows,material 18 is fed between first forming conveyor 41 and second formingconveyor 42. First forming conveyor 41 has knife portions 43 which, incooperation with support portions 44 of second forming conveyor 42,create creases 22 in material 19. Material 19 is provided uncreased,with a connector in the form of beads of adhesive 25 at intervals alongits length. Material 19 is joined at creases 22 to material 18 by thesebeads of adhesive. The resulting shade structure will have nooutwardly-pointing creases, and will have a smoothly drooping front wallportion in accordance with the teaching of the present invention.

I claim:
 1. A cellular shade for covering an architectural openingcomprising a first sheet of planar unpleated flexible material having awidth and a length, said first sheet defining a set of joint linesextending across the width thereof and spaced apart along the lengththereof, a second sheet of flexible material having a width and alength, the width of said second sheet being substantially equal to thewidth of said first sheet and the length of said second sheet beinglonger than the length of said first sheet, said second sheet having aset of joint lines extending across the width thereof and spaced apartalong the length thereof, the spacing between said joint lines on saidsecond sheet being substantially greater than the spacing between saidjoint lines on said first sheet, a connector fixedly joining said firstsheet at said joint lines thereon to said second sheet at correspondingjoint lines thereon to form a plurality of parallel cells extendingacross the width of said sheets, said first sheet defining a smooth(non-creased) planar unpleated rear wall of each of said cells and saidsecond sheet defining the front wall of each of said cells, which saidfront wall forms a curved drooping surface projecting outwardly and awayfrom the back wall of each cell.
 2. A cellular shade as defined in claim1 wherein said joint lines on said second sheet of flexible material arecreases.
 3. A cellular shade as defined in claim 1 further including ahead rail to which a top portion of both the first and second sheets areattached and a bottom rail to which a bottom portion of each of thefirst and second sheets is attached, and cords secured to said bottomrail and extending upwardly through each of said cells and into saidhead rail whereby the bottom rail can be elevated by said cords towardthe top rail.
 4. A cellular shade as defined in claim 1 wherein saidcurved drooping surface has a lowermost edge and said lowermost edge isat least as low as the lowermost joint line corresponding to theassociated cell.